Studies on the cardiovascular actions of chlorpromazine. III. Effects on cerebral blood flow, blood pressure, and electrocorticogram, as recorded simultaneously.

Abstract

In curarized dogs under artificial respiration, it was observed that (a) chlorpromazine in high and repeated doses (5 to 20 mg/kg ) can induce marked fall in blood pressure, tachycardia, and increased cerebral blood flow, (b) previous injections of similar high doses of chlorpromazme do not abolish either the pressor responses or cortical stimulation (outbursts) induced by metrazol, and both agents appear rather to lead to enhanced cortical outbursts, (c) chlorpromazme also does not affect the cortical stimulation (E E G changes) following injections of nikethamide, picrotoxin, or amphetamine,but antagonizes the blood pressure responses to these agents, (d) after ganglionic-blockade (ansolysen or hexamethonium) cortical changes induced by chlorpromazme are not prevented, but its depressor response is lessened by ansolysen, but on the contrary enhanced by hexamethonium, (e) after sympathetic blockade (hydergin) both the central stimulation and pressor responses to metrazol are prevented, but the depressor response to chlorpromazme is antagonized and combined hyderginmetrazol treatment appears to prevent the usually observed depressor effects of excessive chlorpromazine injections, and (f) diethazine appears to exert similar actions to those of chlorpromazine, but its effects are less sustained.